Wuraola A. Shokunbi

The psychosocial problems of sickle cell disease sufferers and their methods of coping

We interviewed 170 sickle cell disease (SCD) patients (mean age 25 years) with a modified version of the Frankfurter Befindlichkeitskala (FBS, 33-item) and the 12-item General Health Questionnaire (GHQ-12), with a view to highlighting the psychosocial issues which worry them, the way they cope with these problems, and the factors associated with these issues. The mean FBS score of SCD patients was comparable with those of insulin dependent diabetics, but significantly higher than that of non-insulin dependent diabetics. The FBS scores were significantly correlated with GHQ-12 scores. Feelings of inadequacy of social contact were significantly associated with high FBS and GHQ scores. Some common complaints were: the limitations illness placed on social life; depressive feelings; abnormal habitus; suicidal ideation during crises; and the burden of illness on the family. They frequently resorted to prayers as a method of coping, as most had no clear ideas on how to deal with these issues. Worries over psychosocial consequences of SCD, seem to add considerably to the burden of illness, and clinicians will offer better care to patients if they routinely enquire into some of these issues and offer health education and counselling in a group setting.

Circulatory hepcidin is associated with the anti-inflammatory response but not with iron or anemic status in childhood malaria

Cerebral malaria (CM) and severe malarial anemia (SMA) are the most serious life-threatening clinical syndromes of Plasmodium falciparum infection in childhood. Therefore, it is important to understand the pathology underlying the development of CM and SMA as opposed to uncomplicated malaria (UM). Increased levels of hepcidin have been associated with UM, but its level and role in severe malarial disease remains to be investigated. Plasma and clinical data were obtained as part of a prospective case-control study of severe childhood malaria at the main tertiary hospital of the city of Ibadan, Nigeria. Here, we report that hepcidin levels are lower in children with SMA or CM than in those with milder outcome (UM). While different profiles of pro- and anti-inflammatory cytokines were observed between the malaria syndromes, circulatory hepcidin levels remained associated with the levels of its regulatory cytokine interleukin-6 and of the anti-inflammatory cytokine inerleukin-10, irrespective of iron status, anemic status, and general acute-phase response. We propose a role for hepcidin in anti-inflammatory processes in childhood malaria.

Affinity Proteomics Reveals Elevated Muscle Proteins in Plasma of Children with Cerebral Malaria

Systemic inflammation and sequestration of parasitized erythrocytes are central processes in the pathophysiology of severe Plasmodium falciparum childhood malaria. However, it is still not understood why some children are more at risks to develop malaria complications than others. To identify human proteins in plasma related to childhood malaria syndromes, multiplex antibody suspension bead arrays were employed. Out of the 1,015 proteins analyzed in plasma from more than 700 children, 41 differed between malaria infected children and community controls, whereas 13 discriminated uncomplicated malaria from severe malaria syndromes. Markers of oxidative stress were found related to severe malaria anemia while markers of endothelial activation, platelet adhesion and muscular damage were identified in relation to children with cerebral malaria. These findings suggest the presence of generalized vascular inflammation, vascular wall modulations, activation of endothelium and unbalanced glucose metabolism in severe malaria. The increased levels of specific muscle proteins in plasma implicate potential muscle damage and microvasculature lesions during the course of cerebral malaria.

Malaria Induces Anemia through CD8 + T Cell-Dependent Parasite Clearance and Erythrocyte Removal in the Spleen

ABSTRACT  Severe malarial anemia (SMA) in semi-immune individuals eliminates both infected and uninfected erythrocytes and is a frequent fatal complication. It is proportional not to circulating parasitemia but total parasite mass (sequestered) in the organs. Thus, immune responses that clear parasites in organs may trigger changes leading to anemia. Here, we use an outbred-rat model where increasing parasite removal in the spleen escalated uninfected-erythrocyte removal. Splenic parasite clearance was associated with activated CD8+ T cells, immunodepletion of which prevented parasite clearance. CD8+ T cell repletion and concomitant reduction of the parasite load was associated with exacerbated (40 to 60%) hemoglobin loss and changes in properties of uninfected erythrocytes. Together, these data suggest that CD8+ T cell-dependent parasite clearance causes erythrocyte removal in the spleen and thus anemia. In children infected with the human malaria parasite Plasmodium falciparum, elevation of parasite biomass (not the number of circulating parasites) increased the odds ratio for SMA by 3.5-fold (95% confidence intervals [CI95%], 1.8- to 7.5-fold). CD8+ T cell expansion/activation independently increased the odds ratio by 2.4-fold (CI95%, 1.0- to 5.7-fold). Concomitant increases in both conferred a 7-fold (CI95%, 1.9- to 27.4-fold)-greater risk for SMA. Together, these data suggest that CD8+-dependent parasite clearance may predispose individuals to uninfected-erythrocyte loss and SMA, thus informing severe disease diagnosis and strategies for vaccine development. IMPORTANCE Malaria is a major global health problem. Severe malaria anemia (SMA) is a complex disease associated with partial immunity. Rapid hemoglobin reductions of 20 to 50% are commonly observed and must be rescued by transfusion (which can carry a risk of HIV acquisition). The causes and risk factors of SMA remain poorly understood. Recent studies suggest that SMA is linked to parasite biomass sequestered in organs. This led us to investigate whether immune mechanisms that clear parasites in organs trigger anemia. In rats, erythropoiesis is largely restricted to the bone marrow, and critical aspects of the spleen expected to be important in anemia are similar to those in humans. Therefore, using a rat model, we show that severe anemia is caused through CD8+ T cell-dependent parasite clearance and erythrocyte removal in the spleen. CD8 activation may also be a new risk factor for SMA in African children. Malaria is a major global health problem. Severe malaria anemia (SMA) is a complex disease associated with partial immunity. Rapid hemoglobin reductions of 20 to 50% are commonly observed and must be rescued by transfusion (which can carry a risk of HIV acquisition). The causes and risk factors of SMA remain poorly understood. Recent studies suggest that SMA is linked to parasite biomass sequestered in organs. This led us to investigate whether immune mechanisms that clear parasites in organs trigger anemia. In rats, erythropoiesis is largely restricted to the bone marrow, and critical aspects of the spleen expected to be important in anemia are similar to those in humans. Therefore, using a rat model, we show that severe anemia is caused through CD8+ T cell-dependent parasite clearance and erythrocyte removal in the spleen. CD8 activation may also be a new risk factor for SMA in African children.

Severe childhood malaria syndromes defined by plasma proteome profiles

Background Cerebral malaria (CM) and severe malarial anemia (SMA) are the most serious life-threatening clinical syndromes of Plasmodium falciparum infection in childhood. Therefore it is important to understand the pathology underlying the development of CM and SMA, as opposed to uncomplicated malaria (UM). Different host responses to infection are likely to be reflected in plasma proteome-patterns that associate with clinical status and therefore provide indicators of the pathogenesis of these syndromes. Methods and Findings Plasma and comprehensive clinical data for discovery and validation cohorts were obtained as part of a prospective case-control study of severe childhood malaria at the main tertiary hospital of the city of Ibadan, an urban and densely populated holoendemic malaria area in Nigeria. A total of 946 children participated in this study. Plasma was subjected to high-throughput proteomic profiling. Statistical pattern-recognition methods were used to find proteome-patterns that defined disease groups. Plasma proteome-patterns accurately distinguished children with CM and with SMA from those with UM, and from healthy or severely ill malaria-negative children. Conclusions We report that an accurate definition of the major childhood malaria syndromes can be achieved using plasma proteome-patterns. Our proteomic data can be exploited to understand the pathogenesis of the different childhood severe malaria syndromes.

Plasma Fibrinogen Levels in Nigerian Homozygous (Hb SS) Sickle Cell Patients

The plasma fibrinogen levels in 50 Nigerian sickle cell disease (Hb SS) patients in steady state and 50 healthy age and sex-matched (Hb AA) control subjects were determined for the purpose of assessing their baseline values. The fibrinogen levels were assessed using two methods, the clot weight and Clauss, on all the samples for the purpose of comparison. It was observed in this study that the Hb SS patients had significantly higher fibrinogen levels than the healthy Hb AA control subjects, both by the clot weight method (p < 0.001) and the Clauss (p < 0.005). The mean fibrinogen levels (4.1 ± 2.1 g/L) of the Hb SS patients as determined by the clot weight method, were significantly higher than the values (2.2 ± 0.3 g/L) obtained by the Clauss method. The mean values for the two methods were 2.8 ± 0.9 and 2.0 ± 0.08 g/L, respectively, among the control individuals with a statistically significant difference (p < 0.005). Estimation of the plasma fibrinogen levels in sickle cell disease patients might be a useful indicator of hyper coagulability, while early diagnosis may help to prevent vaso-occlusive crises in these patients.

The IL17F and IL17RA Genetic Variants Increase Risk of Cerebral Malaria in Two African Populations

ABSTRACT Cerebral malaria (CM) is a neurological complication of infection with Plasmodium falciparum that is partly caused by cytokine-mediated inflammation. It is not known whether interleukin-17 (IL-17) cytokines, which regulate inflammation, control the development of CM. To evaluate the involvement of IL-17 cytokines in CM, we analyzed 46 common polymorphisms in IL17A, IL17F, and IL17RA (which encodes the common receptor chain of the members of the IL-17 family) in two independent African populations. A case-control study involving 115 Nigerian children with CM and 160 controls from the community (CC) showed that IL17F reference single nucleotide polymorphism (SNP) 6913472 (rs6913472) (P = 0.004; odds ratio [OR] = 3.12), IL17F rs4715291 (P = 0.004; OR = 2.82), IL17RA rs12159217 (P = 0.01; OR = 2.27), and IL17RA rs41396547 (P = 0.026; OR = 3.15) were independently associated with CM. A replication study was performed in 240 nuclear Malian family trios (two parents with one CM child). We replicated the association for 3 SNPs, IL17F rs6913472 (P = 0.03; OR = 1.39), IL17RA rs12159217 (P = 0.01; OR = 1.52), and IL17RA rs41396547 (P = 0.04; OR = 3.50). We also found that one additional SNP, IL17RA rs41433045, in linkage disequilibrium (LD) with rs41396547, was associated with CM in both Nigeria and Mali (P = 0.002; OR = 4.12 in the combined sample). We excluded the possibility that SNPs outside IL17F and IL17RA, in strong LD with the associated SNPs, could account for the observed associations. Furthermore, the results of a functional study indicated that the aggravating GA genotype of IL17F rs6913472 was associated with lower IL-17F concentrations. Our findings show for the first time that IL17F and IL17RA polymorphisms modulate susceptibility to CM and provide evidence that IL-17F protects against CM.

Plasma levels of some blood coagulation parameters in Nigerian homozygous sickle cell patients (HbSS) in steady state

Abstract The plasma levels of some blood coagulation parameters; prothrombin time, (PT), partial thromboplastin time with kaolin (PTTK), thrombin clotting time, (TCT), fibrinogen and factor X assay were determined in 50 Nigerian homozygous (HbSS) patients and 50 HbAA healthy individuals for the purpose of assessing their baseline values and susceptibility of patients with sickle cell disease (SCD) to hyper coagulability. Standard procedures were used for all variables. The mean age of the study participants was 21.7 ± 5.0 years. The mean PT of 13.7 ± 1.4s in HbSS patients was found to be significantly longer than the mean PT value of 12.9 ± 1.0 in HbAA control subjects (p < 0.001). The mean PTTK values of 46.0 ± 9.6s in HbSS patients was also found to be significantly higher than the 41.0 ± 3.7s recorded among the control subjects (p < 0.001). The mean TCT of 6.4 ± 0.8s in HbSS patients was however found to be significantly lower than the mean value of 10.6 ± 0.8s obtained in the control group. Fibrinogen level (4.1 ± 2.1 g/l) in HbSS patients and 2.8 ± 0.9 g/l in HbAA controls was also found to be significantly different (p < 0.001). Factor X level in the sickle cell patients, (64.6 ± 14.9%) was equally found to be significantly lower than that of the apparently healthy HbAA control individuals (95.2 ± 7.2%) (p < 0.001).

A Functional IL22 Polymorphism (rs2227473) Is Associated with Predisposition to Childhood Cerebral Malaria

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection. This encephalopathy is characterized by coma and is thought to result from mechanical microvessel obstruction and an excessive activation of immune cells leading to pathological inflammation and blood-brain barrier alterations. IL-22 contributes to both chronic inflammatory and infectious diseases, and may have protective or pathogenic effects, depending on the tissue and disease state. We evaluated whether polymorphisms (n = 46) of IL22 and IL22RA2 were associated with CM in children from Nigeria and Mali. Two SNPs of IL22, rs1012356 (P = 0.016, OR = 2.12) and rs2227476 (P = 0.007, OR = 2.08) were independently associated with CM in a sample of 115 Nigerian children with CM and 160 controls. The association with rs2227476 (P = 0.01) was replicated in 240 nuclear families with one affected child from Mali. SNP rs2227473, in linkage disequilibrium with rs2227476, was also associated with CM in the combined cohort for these two populations, (P = 0.004, OR = 1.55). SNP rs2227473 is located within a putative binding site for the aryl hydrocarbon receptor, a master regulator of IL-22 production. Individuals carrying the aggravating T allele of rs2227473 produced significantly more IL-22 than those without this allele. Overall, these findings suggest that IL-22 is involved in the pathogenesis of CM.

CD4+ T Lymphocytes count in sickle cell anaemia patients attending a tertiary hospital

Background: Sickle cell haemoglobin (HbS) is the commonest abnormal haemoglobin and it has a worldwide distribution. Reports have shown that patients with sickle cell anaemia (HbSS) have an increased susceptibility to infection leading to increased morbidity and mortality. Impaired leucocyte function and loss of both humoral and cell-mediated immunity are some of the mechanisms that have been reported to account for the immunocompromised state in patients with sickle cell disease. This study was carried out to determine the CD4+ T lymphocytes count in patients with sickle cell anaemia. Materials and Methods: A comparative cross-sectional study of 40 sickle cell anaemia patients in steady state (asymptomatic for at least 4 weeks) attending haematology clinic and 40 age and sex-matched healthy HbA control were recruited into the study. Both HbS patients and the controls were HIV negative. The blood samples obtained were analyzed for CD4+ T cell by Flow cytometry. Results: The study found that there was no significant difference in the number of CD4+ T lymphocyte count between individuals with sickle cell anaemia and HbA (1016 ± 513 cells/μL vs 920 ± 364cells/μL). Conclusion: It is recommended that the functionality of CD4+ T lymphocyte should be considered rather than the number in further attempt to elucidate the cellular immune dysfunction in patients with sickle cell anaemia.